The new exhibit at the Arles museum covers not just the remarkable contemporary bust of Julius Caesar, carved during his lifetime in 46 B.C. and portraying him as the middle aged guy he was, but also 500 other artifacts, the fruits of 20 years of perilous and frustrating dives in the Rhône.

The murky waters, strong currents and local fauna made these dives hard work. The team were ready to give up, in fact, when they found the bust of Caesar. After that, of course they had renewed purpose. They’ve been salvaging major Roman artifacts as recently as this year.

The “unifying theme” in “Caesar, the Rhône for Memory”, running to September 2010, is “to maintain the feeling of going on a journey with the archaeologist, following every stage of their work from the site of the digs right up to the restoration and exhibition of the artifacts”, says its designer Pierre Berthier.

The collection shows ancient Arles was not only a port and place of passage, but “decorated” and “monumental” says Long, “an ostentatious facade aiming to display Rome’s wealth and power”.

The most stunning finds are together in the last room of the exhibition that Long calls “the saint of saints”.

Alongside Caesar is the 1.8-metre (six-foot) marble statue of the god Neptune dating from the beginning of the third century AD, and a bronze satyr with its hands tied behind its back.

There’s also a bronze Victory, a head of Juno or Venus, piles of metal ingots, tools, amphorae, oil lamps, an assortment of slice-of-life remnants from 15 different shipwrecks.

When the exhibit ends next September, all the artifacts on display will be added to the museum’s permanent collection.